The present invention concerns pharmaceutical compositions for promoting the healing of wounds or fibrotic disorders, in particular for promoting the healing of wounds or fibrotic disorders with reduced scarring.
By xe2x80x9cwounds or fibrotic disordersxe2x80x9d is meant any condition which may result in the formation of scar tissue. In particular, this includes the healing of skin wounds, the repair of tendon damage, the healing of crush injuries, the healing of wounds to the eye, including wounds to the cornea, the healing of central nervous system (CNS) injuries, conditions which result in the formation of scar tissue in the CNS, scar tissue formation resulting from strokes, and tissue adhesion, for example, as a result of injury or surgery (this may apply to e.g. tendon healing and abdominal strictures and adhesions). Examples of fibrotic disorders include pulmonary fibrosis, glomerulonephritis, cirrhosis of the liver, systemic sclerosis, scleroderma and proliferative vitreoretinopathy.
By xe2x80x9creduced scarringxe2x80x9d is meant reduced level of scarring relative to an untreated wound or fibrotic disorder.
In particular, there is a lack of compositions for promoting the healing of wounds or fibrotic disorders with reduced scarring. Scar tissue formation, although providing mechanical strength to a healed wound, can be unsightly and may impair the function of the tissue.
This is particularly the case in wounds which result in scar tissue formation in the CNS, the scar tissue inhibiting the reconnection of severed or re-growing nerve ends, so significantly affecting their function.
There is also a lack of compositions for treating and promoting the healing of chronic wounds, for example venous ulcers, diabetic ulcers and bed sores (decubitus ulcers), especially in the elderly and wheel chair bound patients. Such compositions may be extremely useful in patients where wound healing is either slow or in whom the wound healing process has not yet started. Such compositions may be used to xe2x80x9ckick-startxe2x80x9d wound healing and may then be used in combination with compositions for promoting healing with reduced scarring. Hence not only may a chronic wound be healed, but it may be healed with reduced scarring.
IL-10 (Interleukin-10) was originally identified as a product of Th2 cells (Fiorentino, D. F. and Moddman, T. R., 1989, J. Exp. Med., 170: 2081-2095) but was also independently identified (O""Garra, A. et al., 1990, Internal Immunol., 2: 821-823) as a product of B-cell lymphomas that prolonged the survival of mast cells and enhanced proliferation of thymocytes.
Molecular characterisation of human and murine IL-10 by Moore, K. W. et al. (1990, Science, 248: 1230-1234) and Vieira, P.et al. (1991, Proc. Natl. Acad. Sci. USA, 88: 1172-1176) showed that there was an 80% homology of their nucleotide sequences. Mouse IL-10 (mIL-10) protein consists of 157 amino acids with two potential N-glycosylation sites although glycosylation is not essential for the biological activities of mIL-10. Human IL-10 (hIL-10) protein consists of 160 amino acids with one potential N-glycosylation site which is not used (Vieira et al., 1991). Both mIL-10 and hIL-10 contain four cysteine residues that form two intramolecular disulphide bonds generating biologically active homodimers with molecular weights of 32 kDa and 39 kDa respectively, and it is not clear whether monomeric forms of IL-10 are biologically active. Although there is 80% homology between hIL-10 and mIL-10, only hIL-10 acts on both human and mouse cells, whereas mIL-10 has species specificity activity (Vieira et al., 1991; Kim, J. M. et al., 1992, J. Immunol., 148:3618-3623).
There are many cellular sources and major biological activities of IL-10, all of which may play some role in the wound microenvironment. It has been shown that IL-10 possesses many stimulatory and inhibitory effects-van Vlasselar et al. (1994, J. Cell Biol., 124: 569-577) showed that IL-10 inhibited TGF-xcex2 synthesis required for osteogenic commitment of mouse bone marrow cells, and hence the resulting mineralised matrix, whereas Go et al (1990, J. Exp. Med., 172: 1625-1631) showed IL-10 to be a novel B-cell stimulatory factor. IL-10 has also been shown by Bogdan et al. (1991, J. Exp. Med., 174: 1549-1555) to directly act on macrophages and inhibit their subsequent activation and hence release of pro-inflammatory cytokines (see also Berg. D. J. et al., 1995, J. Exp. Med., 182: 99-10; Chernoff, A. E. et al., 1995, J. Immunol. 154 (10): 5492-5499).
Despite the aforementioned studies of cytokines, the present inventor has found that, surprisingly, IL-10 may be used to promote the healing of wounds or fibrotic disorders with reduced scarring. It appears that by inhibiting inflammation at a wound site or site of a fibrotic disorder, in particular at an early stage after wounding/onset, there is a xe2x80x9cknock-onxe2x80x9d effect upon the resulting collagen matrix, resulting in an improved architecture and reduced scarring. This result is particularly surprising since in the short-term, there was no inhibition of re-epithelialisation or early wound repair, whilst in the longer-term, it improved the quality of later scar formation and reduced scarring.
According to the present invention there is provided IL-10 or a fragment or a partially modified form thereof for use in promoting the healing of wounds or fibrotic disorders with reduced scarring.
By xe2x80x9cfragment or partially modified form thereofxe2x80x9d is meant a fragment or partially modified form of IL-10 which retains the anti-inflammatory healing functionality of IL-10, although it may of course have additional functionality. Partial modification may, for example, be by way of addition, deletion or substitution of amino acid residues. For example, a substitution may be a conserved substitution. Hence the partially modified molecules may be homologues of IL-10. They may, for example, have at least 40% homology with IL-10. They may for example have at least 50, 60, 70, 80, 90 or 95% homology with IL-10.
IL-10 or a fragment or a partially modified form thereof may be for use in conjunction with a pharmaceutically acceptable carrier, diluent or excipient.
IL-10 or a fragment or a partially modified form thereof may be for use in conjunction with a composition for promoting the healing of wounds of fibrotic disorders with reduced scarring.
IL-10 or a fragment or a partially modified form thereof may be for use in conjunction with a composition for promoting the healing of chronic wounds.
Also provided according to the present invention is a method of promoting the healing of wounds or fibrotic disorders with reduced scarring comprising the use of IL-10 or a fragment or a partially modified form thereof.
IL-10 or a fragment or a partially modified form thereof may be administered to a wound site or site of a fibrotic disorder.
IL-10 or a fragment or a partially modified form thereof may be administered at a concentration of between about 1 xcexcM and about 10 xcexcM. It may be administered at a concentration of between about 2.5 xcexcM and about 5 xcexcM.
IL-10 or a fragment or a partially modified form thereof may be administered immediately prior to wound healing, but may be effective if administered within about 7 days of wounding. It could be administered on at least two occasions.
The method may be used in conjunction with a method or composition for promoting the healing of wounds or fibrotic disorders with reduced scarring.
The method may be used in conjunction with a method or composition for promoting the healing of chronic wounds.
The invention will be further apparent from the following example, with reference to the several figures of the accompanying drawings, which shows, by way of example only, compositions and methods of promoting the healing of wounds or fibrotic disorders with reduced scarring.